Grabbed from my furl.
iPod’s are probably the greatest portable device ever made, but that doesn’t mean they’re perfect. One of the biggest problems with the iPod+iTunes combination is that for some reason they decided to store local preferences on the iPod… thus making them distinctly not local. What this means is that if you have one computer set-up to auto-sync your library, and you want to use your iPod on another computer, each time you plug it in iTunes will offer to erase your iPod’s music collection for you. Not cool.